Camera device, method of manufacturing a camera device, wafer scale package

ABSTRACT

The invention relates to a camera device and a method for manufacturing such a device. The camera device comprises an image capturing element, a lens element for imaging an object at the image capturing element and a spacer means for maintaining a predetermined distance along the main optical axis though the lens and the image capturing element, and lens substrate for carrying the lens wherein the spacer means comprises an adhesive layer. This enables a mass manufacturing process wherein parts of the individual camera elements can be manufactured in manifold on different substrates, after which the different substrates are stacked, aligned and joined via adhesive layers. In the manufacturing process the different distances between the plates and the wafers are adjusted and maintained via the spacer means comprising the adhesive layers. From the stack individual camera devices are sawn out.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from PCT International Application No.PCT/IB2003/003920, having an International filing date of Sep. 16, 2003.

BACKGROUND OF THE INVENTION

The invention relates to a camera device comprising an image capturingelement, a lens element for projecting an object on the image capturingelement, a spacer means for maintaining a predetermined distance betweenthe lens and the image capturing element, and a lens substrate forcarrying the lens.

The invention also relates to a method for manufacturing a cameradevice, a wafer scale package comprising a base substrate having aplurality of image capturing elements, and an optical assembly for usein a process for manufacturing a camera device.

Camera devices of this type are used in, for instance small portabledevices such as mobile telephones, personal digital assistants (PDAs)and laptop computers.

A camera device as mentioned in the opening paragraph is disclosed inthe Japanese patent application published under number JP-2002/139662.The known camera device comprises an image pick-up element mounted on asubstrate, and a lens support carrying one or more lenses. The lenssupport is integrally formed with the lens and is fastened to the imagepick-up element whereby the lens support takes care of an accurateposition in the direction of a main optical axis through the lenses onthe image pick-up element. In a manufacturing process the individualimage pick-up element, lens support, and lens are stacked and joinedtogether. In order to obtain a high-quality image of an object on theimage pick-up element, the dimensions of the lens support in thedirection of the main optical axis should have a high accuracy.Furthermore positioning of these parts relative to each other should beaccurate.

BRIEF SUMMARY OF THE INVENTION

A disadvantage of the known camera device is that the manufacturingprocess each lens support has to be adjusted separately relative to theimage pick-up element in each camera device, so there is littlepossibility to manufacture the known camera device in an efficient massproduction process while maintaining a high positioning accuracy.

It is inter alia an object of the invention to provide a camera deviceof the type mentioned in the opening paragraph, having an increasedcapability for an efficient mass manufacturing process with a highpositioning accuracy.

To this end the invention provides camera device as defined in theopening paragraph which is characterized in that the spacer meanscomprises an adhesive layer.

In this arrangement the lens substrate including the lens element andthe spacer means comprising the adhesive layer, can be positioned andaligned along the main optical axis through the lens element and theimage capturing element, after which a predetermined distance is setbetween the lens element and the image capturing device. After hardeningthe adhesive layer this predetermined distance is maintained by thespacer means. This arrangement provides increased capabilities for massmanufacturing wherein a plurality of image capturing elements, lenselements and spacer means can be manufactured on a base substratecomprising the imaging elements and a lens substrate respectively,whereby the base substrate and the lens substrate are stacked and joinedwith a high accuracy and the individual camera devices are separatedfrom the stack. The hardening of the adhesive layer can be performed incase of an ultra-violet curable adhesive by UV radiation or in case of athermo-hardening adhesive by heating the adhesive layer.

U.S. Pat. No. 6,285,064 introduces a wafer scale package for solid stateimage sensor integrated circuits, whereby arrays of micro lenses areplaced on top of a wafer having the image sensors formed thereon. Anadhesive matrix is placed atop of the wafer. The adhesive matrix hasopenings that align with the micro lens arrays on top of the wafer. Acover glass is then placed over the adhesive and the adhesive isactivated to secure the cover glass to the wafer. Because the adhesivehas openings above the micro lensed portion distortion or reduction ofthe lens effect by the adhesive shall be avoided.

It is a further object of the invention to provide a method for anefficient mass production process of a camera device. This object isachieved by a method for manufacturing a camera device, characterized bythe steps of

-   -   providing a lens substrate comprising a plurality of lens        elements, the lens substrate comprising an adhesive layer;    -   stacking the lens substrate and a base substrate comprising a        plurality of image capturing elements;    -   aligning the lens substrate and the base substrate along main        optical axes through respective lens elements and associated        image capturing elements;    -   setting the distance between the lens elements and the        associated image capturing elements along the main optical axes        through the lens elements and the associated image capturing        elements;    -   hardening the adhesive layer; and    -   separating camera devices from the stack of the lens substrate        and the base substrate.

In this process the camera devices are manufactured by stacking a lenssubstrate comprising a plurality of lens elements, spacer means in theform of a spacer substrate and a base substrate containing a pluralityof image capturing elements. The predetermined distances along theoptical axis through the individual lens elements and the associatedimage capturing elements between the different substrates can beaccurately adjusted after the stacking of the substrates and maintainedby hardening of the adhesive layer between the different substrates.After completing the stack, the individual camera devices can beseparated from the stack. This process yields relatively cheap cameradevices which are suitable for use in small electronic equipment, suchas mobile phones and personal digital assistants.

It is a further object of the invention to provide a wafer scale packagefor an efficient mass production of a camera device. This object isachieved by a wafer scale package comprising a base substrate having aplurality of image capturing elements, characterized in that it furthercomprises a lens substrate having a plurality of lens elementsassociated with respective image capturing elements, and a spacer meansfor maintaining a predetermined distance between the lens substrate andthe base substrate, whereby the position of the lens substrate relativeto the base substrate is fixated by means of an adhesive layer.

In this wafer scale package the lenses are already aligned relative tothe corresponding image capturing elements and the distance between thelenses and the corresponding image capturing elements is accuratelyadjusted. In this way it is not required to position individual lenselements relative to corresponding individual image capturing elements,thereby simplifying the manufacturing of camera devices.

It is a further object of the invention to provide an optical assemblyfor an efficient mass production of a camera device. This object isachieved by An optical assembly for use in a process for manufacturing acamera device according to the invention, characterized in that itcomprises a lens substrate having a plurality of lens elements.

By stacking the optical assembly and a base substrate comprising a imagecapturing elements corresponding to the plurality of lens elements it ispossible to position the lens elements relatively to the image capturingelements for all lens elements simultaneously. In this way it is notnecessary to position individual lens elements relative to individualimage capturing elements in a later stage of production.

Preferably the optical assembly has area dimensions corresponding to thearea dimensions of the base substrate comprising the image capturingelements.

In embodiments the adhesive layer comprises an ultra-violet curing resinor a thermo-hardening resin.

In a further embodiment the adhesive layer has the shape of a rimsituated outside the projection of the hole on the spacer means,co-axially positioned with the main optical axis of the lens element. Inthis way, no adhesive material is in the optical path between the lenselement and the image capturing element.

In a further embodiment the spacer means comprises a cover substrate anda spacer substrate. The cover substrate protects the image capturingelement against possible damage during further manufacturing processsteps.

In a further embodiment the spacer substrate comprises a hole coaxiallypositioned relative to a main optical axis of the lens element wherebythe side of the hole is provided with an anti-reflection layer. Thisarrangement reduces reflection within the camera device, therebyenhancing its performance.

In a further embodiment the adhesive layer can be provided between theimage capturing element and the spacer substrate; and also between thespacer substrate and the cover substrate. This arrangement enablesaccurate adjustment after each separate step of stacking.

In a further embodiment the lens element is of a replication type. Thesereplication type lenses enable manufacturing of high quality lenses atlow costs. Suitable materials for manufacturing replication type lensesare in principle all monomers with a group that can be polymerized.

In a further embodiment the lens element is formed as a convexity in thelens substrate. This simplifies the manufacturing of the lens elements.

In a further embodiment the lens element is formed as a concavity in thelens substrate. In this arrangement the lens substrate can be part ofthe spacer means. In this way larger distances between the lens and theimage capturing element can be obtained by increasing the thickness ofthe lens substrate, without increasing the complexity of themanufacturing process by introducing a separate spacer substrate.

In a further embodiment the lens substrate is provided with a throughhole whereby the lens element is located within the through hole. Inthis way more flexibility is provided in the shape of the lens and inthe distance between the lens and the image capturing element.

In a further embodiment the lens substrate is provided with an infra-redreflection layer. Solid state image capturing elements are sensitive toinfra-red radiation. By cutting off this infra-red range of thespectrum, the sensitivity of the camera device for infra-red radiationis reduced.

In a further embodiment the lens substrate is provided with ananti-reflection layer. This arrangement avoids reflection in the cameradevice.

These and other aspects of the invention are apparent from and will beelucidated with reference to the embodiments described hereinafter.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

In the drawings:

FIG. 1 is a cross-sectional view of a first embodiment of a cameradevice,

FIG. 2 is a cross-sectional view of a second embodiment of a cameradevice,

FIG. 3 shows a stack of wafer plates obtained after several successivemanufacturing steps, of the camera device before dicing out the cameradevices,

FIG. 4 shows a manufacturing process flow chart of the camera device;

FIG. 5 shows a step of dicing the stack of wafer plates.

FIGS. 6 a to 6 d show, in slice planes, different arrangements for awafer scale package comprising solid-state image sensors, according tothe principle of the present invention;

FIGS. 7 a to 7 d represent simulations of different optical systems foruse in a camera device, wafer scale package, or optical module accordingto the invention;

FIGS. 8 a to 8 e show several steps of the manufacturing of a furtherembodiment of a camera device according to the invention.

FIGS. 9 a to 9 f show, in slice planes, several embodiments of anoptical assembly according to the invention.

FIGS. 10 a to 10 d show, in slice planes, further embodiments of anoptical assembly according to the invention.

The Figures are schematic and not drawn to scale, and, in general, likereference numerals refer to like parts.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 schematically shows a first embodiment of a camera device. Thecamera device 101 comprises an image capturing element 103, a microspacer plate 105 glued to the image capturing element, a cover plate 107glued to the micro spacer plate 105 and a lens substrate 109 providedwith a lens 111. The image capturing element is a Charge Coupled imagingDevice (CCD) or a CMOS imaging device. In general such an imagecapturing element is referred to as a solid-state image sensor (SSIS).The micro spacer plate 105 is provided with a hole for passing imageforming light rays from the lens element 111 to the image capturingelement 103. Preferably, an infra-red reflection coating 119 is providedbetween the lens substrate 109 and the cover plate 107; and ananti-reflex coating 121 is provided over the lens substrate 109 and thelens element 111. A first adhesive layer 113 of approximately 10 μmthickness is present between the micro space plate 105 and the imagecapturing element 103. A second adhesive layer 115 of approximately 100μm thickness is present between the cover plate 107 and the micro spacerplate 105 and a third adhesive layer 117 of approximately 10 μmthickness is present between the lens substrate 109 and the cover plate107. Preferably, the adhesive layers 113, 115, 117 are rim-shaped, theadhesive material being present outside an area coinciding with theprojection of the circumference of the lens element 111 on the surfacesof the micro-spacer plate 105 and the cover plate 107.

The thickness of the micro-space plate 105 is for example 0.4 mm. Thethickness of the cover plate is 0.4 mm and the thickness of the lenssubstrate plate is for example 0.4 mm. Each adhesive layer 113, 115, 117maintains the distance between the different plates to a predetermineddistance with an accuracy of typically 5 μm. In the camera device 101the spacer means is thus formed by the micro-spacer plate 105, the coverplate 107 and the adhesive layers 113, 115, 117.

To prevent ghost imaging on the image capturing element 103 it may beadvantageous to provide an anti-reflection layer on the side wall of themicro-spacer plate 105, thereby by preventing unwanted reflections oflight within the camera device 101. Such an anti-reflection layer can beprovided for instance by coating the side wall of the micro-spacer plate105 with a low reflecting material, for instance with black resist. Thecoating may be applied by means of spraying.

FIG. 2 shows a second embodiment of a camera device. This camera device110 comprises an optical system of two lens elements 111, 127. Anadvantage of the two-lens optical systems is that a relatively stronglens operation is obtained without much aberrations.

Parts in FIG. 2 assigned the same number as in FIG. 1 correspond to thesame elements. Furthermore, FIG. 2 shows a second lens substrate 125stacked on a second spacer place 123 and the first lens substrate 109respectively, aligned along the main optical axis through the secondlens element 127, the first lens element 111 and the image capturingelement 103 and joined by adhesive layers 129, 131. Preferably, adiaphragm 133 is formed from an aluminum layer provided with a holeco-axially positioned with the main optical axis of the lenses 111, 127.

To prevent ghost imaging on the image capturing element 103 it may beadvantageous to provide an anti-reflection layer on the side wall of themicro-spacer plate 105 and/or on the side wall of the second spacerplate 123, thereby by preventing unwanted reflections of light withinthe camera device 110.

A manufacturing method for these camera devices comprises wafer scalemanufacturing steps because multiple image capturing elements aremanufactured and obtained on a substrate, for example, a silicon waferof approximately 20.32 cm diameter (8″). Also the spacer means and lenselements can be manufactured in manifold on substrates. FIG. 3 shows anexploded view of a stack of substrates before the individual cameradevices 110 are diced out. This stack 130 comprises a base substrate 134comprising the silicon wafer 135 containing image capturing elements103, a micro-spacer wafer 137 containing micro-spacer elements 105, acover wafer 139 and a first lens substrate 141 containing lenses 109.All these elements are available on a wafer dimension scale.Furthermore, FIG. 3 shows a second spacer wafer 143, a second lenssubstrate 145 and a further cover wafer 147, necessary to obtain acamera device provided with an optical system of two lenses.

FIG. 4 shows a process flow chart 140 of a method for manufacturingcamera devices. In a process step 120 the first lens substrate 141 ismanufactured by providing an infra-red coating 119 on a glass substrate,followed by a process step P21 of forming the lens elements 111 on theglass substrate via a conventional replication process. In a furtherprocess step P22 the first lens substrate 141 is provided with ananti-reflex coating 121.

The base substrate 134 is manufactured in the following process steps.In a process step P10 a micro-spacer wafer 137 is manufactured byetching holes in a glass substrate of wafer size dimension for example20.32 cm. Alternatives for etching in this process step P10 are: lasercutting, powder blasting and ultrasonic drilling. All these techniquesare well known to a person skilled in the art. In a subsequent step,process step P12, the micro-spacer wafer 137 and the silicon wafer 135containing the image capturing elements, are provided with an adhesivelayer via screen printing, or alternatively, spray coating. The adhesivelayer may consist of for example an ultra-violet curable resin.Furthermore, the micro-spacer wafer 137 and the cover wafer 139 arealigned and the distance along the main optical axis between the coverplate wafer the holes of the micro-spacer wafer 137 and the imagesurface of the associated image capturing elements 103 of the siliconwafer 135 is set to a predetermined value of, for example, 900±5 μm,after which the adhesive layer is cured by ultra-violet radiation. Thehardened adhesive layer 115 maintains the adjusted distance. The joinedwafers 135, 137, 139 form the base substrate 134 containing the imagecapturing elements 103.

In a subsequent process step P14 the base substrate 134 and the lenssubstrate 141 are aligned, set to, a predetermined distance of, forexample 10 μm; and joined together via an ultra-violet (UV) curableadhesive layer 117. In a further subsequent step P15 the individualcamera devices are separated, for example, by sawing.

In order to obtain a camera device 110 comprising an optical system oftwo lens elements 111, 127 some further process steps P40, P41 and P31are required. In process step P30 a second spacer wafer 143 is providedwith holes for image forming rays to pass through. In the process stepP40 the lenses 127 are formed on the second lens substrate via areplication process. Preferably, in a subsequent process step P41 adiaphragm is provided on the lens 127. The diaphragm is formed by analuminum layer with a circular hole coaxially positioned relative to themain optical axis of the lens system. In a subsequent joining step P31the second lens substrate plate 145 and the second spacer wafer 143 arealigned, set to a predetermined distance of for example 1.67 mm; andjoined by an ultra-violet curable adhesive layer 131 of approximately100 μm. In a subsequent process step P23, the sub-assembly of secondlens substrate plate 145 and the second spacer plate 143 is aligned, setto a predetermined distance of for example 121 mm to the first lenssubstrate plate 141, and joined by an ultra-violet curable adhesivelayer 129 of 10 μm.

In the process step P14 this lens substrate assembly 44 and the basesubstrate sub-assembly 142 of process step P13 are aligned, set to apredetermined distance and joined by an ultra-violet curable adhesivelayer 129. Preferably, in this process step a third spacer plate 146 anda second cover plate 147 are stacked on the second lens substrate 145 byan ultra-violet curable layer. In a separating step P15 the cameradevices 110 are sawn out, or separated in another known way, of theassembled stack 150 as diagrammatically shown in FIG. 5. The assembledstack 150 is sawn via a dicing lane 152. The width of the dicing lane isfor example approximately 230 μm. It may be advantageous to apply athermo-hardening adhesive instead of a ultra-violet curing adhesive.

It will be obvious that many variations are possible within the scope ofthe invention without departing from the scope of the appended claims.

In FIGS. 6 a to 6 d are shown, in slice planes, different arrangementsfor a wafer scale package comprising solid state image sensors (SSIS),according to the principle of the present invention. All through theFIGS. 6 a to 6 d there is a silicon wafer 211, comprising an array ofSSIS dies (not illustrated in FIGS. 6 a to 6 d) and a covering glasslayer 231, preferable made of an IR glass. For better illustration,there is only shown a section of the whole wafer, which is indicated bythe dotted line L on the left side of each FIG. 6 a to 6 d. It will benoted that within the arrangement of the silicon wafer 211 and the glasslayer 231, micro lenses may be attached to the photosensitive area ofthe SSIS dies. As to the performance of the camera devices that areobtained by separating the wafer scale package, this will be referred toin FIGS. 7 a to 7 d.

The wafer scale package in FIG. 6 a only comprises a first glass layer231 and a second glass layer providing convex lenses 250 orientated awayfrom surface of the silicon wafer 211. In FIG. 6 b there is the onlychange in comparison to FIG. 6 a that a spacer layer 222 has beeninserted between a first transparent layer 231 and a second transparentlayer 240 containing the lenses 250. As to FIG. 2 c, there is a furtherminor change with respect to FIG. 6 b, here an additional glass layer242 comprising lenses 52 has been inserted between the spacer layer 222and the first glass layer 231. In this embodiment, there is an air gapbetween the two lenses 250, 252 of the wafer scale package. Finally,FIG. 6 d shows an arrangement, again in comparison to FIG. 6 b, whereina additional glass layer 244 with lenses 254 is arranged between thespacer layer 222 and the glass layer 240.

Now reference is made to FIGS. 7 a to 7 d, here the performance of someexamples for camera devices, wafer scale packages, and optical modulesaccording to the present invention are illustrated by way of simulationdiagrams. The simulations give results according to performance anddimensions of a camera device according to the present invention. Allsimulation diagrams read as follows: starting from the left, i.e. thereal image which is to be projected by the optical system, there arelight rays, which are depicted as lines, going through the opticalsystem and crossing each other behind the optical system. The crosspoints of these simulated light rays could be connected by a drawingline, this would lead to the ideal image plane wherein the real imagewould be projected without error. However, since the photosensitive areaof an SSIS is flat, the optical system has to be adapted to a flatphotosensitive area as image plane. Looking at FIG. 7 a shows that anoptical system with only one lens has a very curved image plane andtherefore, produces increasingly low performance towards the edges ofthe image plane. FIGS. 7 b to 7 d display the advantage of a second lensin the optical system, since both lenses work together as to focus andas to flattening of the image plane and thus, the image plane is moreadapted to the photosensitive area. The arrangement in FIG. 7 b has asan advantage that it is very low in height. This is because of the fact,that a large angle for the traveling light can be used in the air cavitybetween the two lenses.

Now reference is made to FIGS. 8 a to 8 e, where several steps of themanufacturing process of a further embodiment of the present inventionare illustrated. As can be seen from top of FIG. 8 a, a micro-spacerlayer 225 for the micro lenses (not illustrated) is mounted on the topside of a silicon wafer 215 comprising solid-state image sensors. In anext step a cover glass layer 235 is attached to the micro-spacer layer225. Onto the cover glass layer 235 is an IR glass layer 236 mounted.Hereafter follows a further step for installing an optical system forthe SSIS on wafer scale. On top of the IR glass layer 236 a wafer levellens holder or lens substrate 260 with cavities 262 for lenses isplaced. This leads to FIG. 8 b. Now referring to FIG. 8 c, after thewafer level lens holder 260 has been glued to the IR glass layer 236,the lenses 270 are mounted into the cavities 262 of the wafer level lensholders 260. In FIG. 8 d can be seen that the camera devices areseparated after mounting of the lenses 270. In a next step such a cameradevice 295 can be installed onto a flex foil 290 for interconnection.Furthermore it may be advantageous to provide a sunshade 280. Thissunshade 280 can be mounted before installation into an application orcan be a part of a housing in which the camera device 295 can beinstalled.

FIGS. 9 a to 9 f show, in slice planes, several embodiments of anoptical assembly according to the invention. The shown opticalassemblies comprise a substrate having a plurality of lens elements. Theoptical assemblies are to be used in a manufacturing process of cameradevices. This can be, for instance, a process similar to the processshown in FIG. 4. In such a process the optical assembly is preferablystacked to a base substrate comprising a plurality of image capturingelements corresponding to the lens elements. Preferably an adhesive isused to join the optical assembly and the base substrate. After thedistance has been set between the respective lens elements andcorresponding image capturing elements, and the lens substrate and thebase substrate have been aligned relatively to each other, the adhesiveis cured. This results in a wafer scale package similar to those shownin FIG. 3, FIG. 5, and FIG. 6. Alternatively, the optical assembly maybe separated into individual lens modules which are stacked toindividual image capturing elements.

The optical assemblies shown in FIGS. 9 a to 9 f are manufactured bymeans of a replication process. In such a process the lenses are usuallymade in whole or in part of polymers or curable liquids that areoptically transparent. The lens substrate is usually made of anoptically transparent material such as for example glass, plastic,resin, or quartz.

FIG. 9 a shows a cross section of an optical assembly 310 comprising aplurality of replication type positive or convex lens elements 311formed on a lens substrate 312. The lens elements may be spherical,aspherical, or anamorphic. FIG. 9 a also shows an individual lens module315, comprising a replication type positive lens element 316 on asubstrate 317, that is obtained by separating the optical assembly 310along the lines 313. For separation, known methods, as for instancedicing can be used.

FIG. 9 b shows a cross section of an optical assembly 320 comprising aplurality of replication type negative or concave lens elements 321formed on a lens substrate 322. The lens elements may be spherical,aspherical, or anamorphic. FIG. 9 b also shows an individual lens module325, comprising a replication type negative lens element 326 on asubstrate 327, that is obtained by separating the optical assembly 320along the lines 323.

FIG. 9 c shows a cross section of an optical assembly 330 comprising aplurality of positive-negative replication type lenses formed in throughholes in the lens substrate 333. FIG. 9 c also shows an individual lensmodule 335, comprising a replication type positive-negative lens element336 formed in a through hole in a substrate 337, that is obtained byseparating the optical assembly 330 along the lines 333. In this casethe substrate 331, 337 does not need to be transparent. This may beadvantageous in preventing unwanted reflection of light in a cameradevice in which the optical module is used. A further advantage of theoptical assembly 330 and the optical module 335 is the by combining apositive lens and a negative lens in this way the resulting stack heightmay be reduced as compared with the optical module and the opticalassembly shown in FIG. 9 d.

FIG. 9 d shows a cross section of an optical assembly 340 comprising aplurality of positive replication type lenses 341 and correspondingnegative replication type lenses 342, both on opposite sides of a lenssubstrate 343. FIG. 9 d also shows an individual lens module 345,comprising a replication type positive lens element 346 and acorresponding negative replication type lens element 348 formed onopposite sides of a lens substrate 347, that is obtained by separatingthe optical assembly 340 along the lines 343.

FIG. 9 e shows a cross section of an optical assembly 350 comprising aplurality of first replication type positive lenses 351 formed on afirst lens substrate 352, separated from a plurality of correspondingsecond replication type positive lenses 354 formed on a second lenssubstrate 355 by means of a spacer substrate 353 having through holescoaxially aligned with the optical axes through respective first lenses351 and second lenses 354. By changing the thickness of the spacersubstrate 353 the distance between the first lenses 351 and thecorresponding second lenses 354 is changed. FIG. 9 e also shows a lensmodule 360 that is obtained by separating the optical assembly 350 alongthe lines 356. It comprises a first positive replication type lenselement 361 formed on a first lens substrate 362, which is separatedfrom a corresponding second lens element 364 formed on a second lenssubstrate 364 by means of a spacer substrate 363 having a through holecoaxially aligned with the optical axis through the first lens element361 and the second lens element 364.

FIG. 9 f shows a cross section of an optical assembly 370 comprising aplurality of first replication type positive lenses 371 and a pluralityof corresponding second replication type negative lenses 373 formed onopposite sides of a first lens substrate 372, joined with a plurality ofcorresponding third replication type positive lenses 374 formed on asecond lens substrate 375 by means of a spacer layer of adhesivematerial (not shown). The respective first lenses 371, and correspondingsecond lenses 373 and third lenses 375 are aligned along the sameoptical axes. FIG. 9 f also shows a lens module 380 that is obtained byseparating the optical assembly 370 along the lines 376. It comprises afirst positive replication type lens element 381 and a correspondingsecond negative replication type lens 383 formed on opposite sides of afirst lens substrate 382, which is joined with a corresponding thirdpositive replication type lens element 384 formed on a second lenssubstrate 384. The first lens element 381, the second lens element 383,and the third lens element 384 have a common optical axis. An advantageof combining the second lens element 383 and the third lens element 384is that the need of a separate spacer substrate may be circumvented.

FIGS. 10 a to 10 d show, in slice planes, further embodiments of anoptical assembly according to the invention. In a similar way as theoptical assemblies shown in FIGS. 9 a to 9 e these optical assembliesare used in the manufacturing of a camera device. The main differencewith the optical assemblies shown in FIGS. 9 a to 9 e is that theoptical assemblies shown in FIGS. 10 a to 10 d comprise pre-shapedsubstrates that are optically transparent. Such pre-shaped substratescan be made for instance by hot-forming of a suitable transparentmaterial. This involves heating the substrate material and forming it byusing a mould. Suitable substrate materials are, for instance, glass,quartz, and suitable transparent plastics.

FIG. 10 a shows an optical assembly 400 comprising a pre-shapedsubstrate 401 having a plurality of convexities 402. The convexityfunction as positive lens elements. To enhance their functioning as lenselements The convexities are covered by a correction layer ofreplication type material 403. FIG. 10 a also shows an individualoptical module 405 that is obtained by separating the optical assembly400 along the lines 404.

FIG. 10 b shows a pre-shaped substrate 411 comprising a plurality ofpositive replication type lens elements 412 formed on one side of apre-shaped substrate 411 and a plurality of depressions or recessedareas 413 corresponding to the lens elements 411 at the other side ofthe substrate 411. An advantage of the shown pre-shaped substrate isthat it integrates the functionality of a lens substrate, as shown inFIGS. 9 a to 9 e, and the functionality of a spacer layer. In this waythe number of components making up a camera device may be reduced,resulting in a more simple assembly and/or a more camera device having alens system that is more accurately aligned with the image capturingelement. FIG. 10 b also shows an individual optical module 415 that isobtained by separating the optical assembly 410 along the lines 414.

FIG. 10 c shows an optical assembly 420 comprising a pre-shapedsubstrate 421 having a plurality of convexities 422 formed at one sideof a substrate 421 and a plurality of depressions 424 formed at theother side of the substrate 421. The convexities 422 function aspositive lens elements. To enhance their functioning as lens elementsthe convexities 422 are covered by a correction layer 423 of replicationtype material. Furthermore the depressions 424 are filled with a layer425 of replication material formed as a negative lens. In this way bothpositive and negative lenses may be integrated in a single substrate.FIG. 10 c also shows an individual optical module 427 that is obtainedby separating the optical assembly 420 along the lines 424.

FIG. 10 d shows an optical assembly 430 comprising a first pre-shapedsubstrate 431 having a plurality of first convexities 432 formed at oneside of a first substrate 431 and a plurality of depressions 434 formedat the other side of the first substrate 431. The first convexities 432function as positive lens elements. To enhance their functioning as lenselements the first convexities 432 are covered by a first correctionlayer 433 of replication type material. Furthermore the depressions 434are filled with a second layer 435 of replication material formed as anegative lens. The optical assembly 430 further comprises a secondpre-shaped substrate 436, joined with the first pre-formed substrate431, having a plurality of second convexities 437 formed at a sideopposing the depressions 434 of the first substrate 431 andcorresponding to the depressions 434. The second convexities 437function as positive lens elements. To enhance their functioning as lenselements the second convexities 437 are covered with a third correctionlayer 438 of replication material. An advantage of the shown firstpre-shaped substrate 431 is that it integrates the functionality of alens substrate and the functionality of a spacer layer. FIG. 10 d alsoshows an individual optical module 440 that is obtained by separatingthe optical assembly 430 along the lines 439.

The embodiments of the present invention described herein are intendedto be taken in an illustrative and not a limiting sense. Variousmodifications may be made to these embodiments by those skilled in theart without departing from the scope of the present invention as definedin the appended claims.

For instance wafer diameters and other dimensions mentioned in thediscussion of the embodiments may be changed. The same holds for thetype of image capturing elements applied.

Furthermore, although above mostly dicing or sawing is mentioned as asuitable technique to separate wafer scale packages or opticalassemblies according to the invention, other known techniques may beapplied, for instance, scribing, laser cutting, etching, or breaking.

1. A camera device comprising an image capturing element, a first lenssubstrate for carrying a first lens element, wherein said first lenselement projects an object on the image capturing element, a spacerlocated between the first lens substrate and the image capturingelement, wherein the spacer comprises first and second adhesive layers,wherein the adhesive layers each comprises one of a ultra-violet curingresin and thermo-hardening resin, and a glass spacer substrate formaintaining a predetermined distance between the first lens substrateand the image capturing element, wherein said spacer substrate isadhered to said image capturing element by means of said first adhesivelayer, wherein a second lens substrate for carrying a second lenselement is stacked on said first lens substrate, aligned along the mainoptical axis through the second lens element, first lens element, spacersubstrate and the image capturing element, wherein the spacer substratecomprises a hole coaxially positioned relative to a main optical axis ofthe lens element.
 2. A camera device according to claim 1, wherein anadhesive layer is present between the second lens substrate and thefirst lens substrate.
 3. A camera device according to claim 1, whereinsaid second lens substrate further comprises a second spacer substrate,wherein said second spacer substrate is adhered to said first lenssubstrate through an adhesive layer.
 4. A camera device according toclaim 3, wherein said second lens substrate is adhered to said secondspacer substrate through an adhesive layer.
 5. A camera device asclaimed in claim 3, wherein the adhesive layer adhering said secondspacer substrate has the shape of a rim outside a projection of the holeon the second spacer substrate coaxially positioned relative to a mainoptical axis of the second lens element.
 6. A camera device as claimedin claim 1, wherein each said adhesive layer comprises an ultra-violetcuring resin.
 7. A camera device as claimed in claim 1, wherein eachsaid adhesive layer comprises a thermo-hardening resin.
 8. A cameradevice as claimed in claim 1, wherein the side of the hole is providedwith an anti-reflection layer.
 9. A camera device as claimed in claim 1,wherein at least one of the lens elements is of a replication type. 10.A camera device as claimed in claim 1, wherein at least one of the lenselements is formed as a convexity in the lens substrate.
 11. A cameradevice as claimed in claim 1, wherein at least one of the lens elementsis formed as a concavity in the lens substrate.
 12. A camera device asclaimed in claim 1, wherein the lens substrate is provided with athrough hole whereby at least one of the lens elements is located withinthe through hole.
 13. A camera device as claimed in claim 1, wherein thelens substrate is provided with an infra-red reflecting layer.
 14. Acamera device as claimed in claim 1, wherein the lens substrate isprovided with an anti-reflection layer.
 15. A camera device as claimedin claim 1, wherein: at least one of said first lens element and saidsecond lens element is formed integrally with the respective one of saidfirst lens substrate and said second lens substrate.
 16. A camera deviceas claimed in claim 1, wherein: said first lens element is formedintegrally with said first lens substrate, and said second lens elementis formed integrally with said second lens substrate.